Metal-insulator-metal (MIM) capacitors are valuable components in memory, logic and analog circuits. For example, MIM capacitors are critical in several mixed signal integrated circuits such as analog frequency tuning circuits, switched capacitor circuits, filters, resonators, up-conversion and down-conversion mixers, and A/D converters.
MIM capacitors are developed with the highest capacitance consistent with the operating voltage. For example, in older CMOS/SiGe generations, the maximum use voltage was 6.5V which has migrated to 5V and 3.3V for newer generations. However, as GaAs chip designs have been migrating into SiGe and RF-CMOS, the need for both high capacitance and high operating voltage MIM capacitors has arisen. As such, different types of MIM capacitors may be needed for different circuit requirements. As an example, low density (high voltage) capacitors are required for power amplifier applications and ADC/DAC converters; whereas, high density capacitors are required for RF filter/coupling and decoupling capacitors. High quality factor (Q) capacitors may also be needed for RF switching. For this reason, there is a need to have MIM capacitors to address different circuit design requirements. However, there is no known economical way to manufacture complimentary MIM capacitors on a single chip to address different circuit design requirements.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.